Comparison of early and late time-controlled adaptive ventilation on pulmonary gas exchange in anesthetized horses.
Abstract: To compare early versus late time-controlled adaptive ventilation (TCAV) for setting airway pressure release ventilation (APRV) on arterial oxygenation in dorsally recumbent anesthetized horses. Methods: A crossover, nonrandomized, experimental study. Methods: Six healthy adult horses. Methods: Each horse underwent two anesthetics: 1) volume-controlled ventilation (VCV) began for 30 minutes before switching to APRV using the TCAV method (late TCAV, TCAV); and 2) ventilation began immediately with TCAV (early TCAV, TCAV). The study lasted 180 minutes, with arterial blood gases and respiratory mechanics recorded at T0 and every 30 minutes. Electrical impedance tomography (EIT) was performed at T0, T30, T90 and T180 to calculate mid-cranial regional ventilation. A two-way repeated measures analysis of variance was used for comparisons. Lung ultrasound (LUS) images were obtained from three horses at baseline (before anesthesia) and at T30, T60, T120 and T180 during each crossover to calculate a mid-caudal LUS score. No statistical analysis was performed on ultrasound data. Results: TCAV showed significantly higher partial pressure of arterial oxygen to fraction of inspired oxygen (PaO/FiO) than TCAV, whereas TCAV did not significantly affect it compared with VCV in the TCAV group. TCAV resulted in significantly higher tidal volumes (V)than TCAV, whereas in the TCAV group, TCAV reduced V compared with VCV. No significant differences were found in respiratory system compliance or airway driving pressure. Both TCAV and TCAV significantly improved dorsal lung ventilation on EIT, but TCAV failed to reverse caudal atelectasis and consolidation seen on LUS, whereas TCAV appeared to prevent it. Conclusions: TCAV improved oxygenation and regional ventilation, whereas TCAV failed to improve respiratory mechanics or oxygenation compared with VCV.
Copyright © 2025 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.
Publication Date: 2025-06-25 PubMed ID: 40707352DOI: 10.1016/j.vaa.2025.06.007Google Scholar: Lookup
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Summary
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The research investigates the effects of early versus late time-controlled adaptive ventilation on oxygen levels in anesthetized horses lying on their backs. The study concludes that early implementation of this ventilation method improves oxygenation and regional ventilation, while a later implementation fails to do so.
Understanding the Experiments
The paper presents its experiment in a crossover, nonrandomized manner, focusing on six healthy adult horses. The study comprises:
- Two different manners of anesthesia: one involving volume-controlled ventilation (VCV) for 30 minutes before switching to airway pressure release ventilation (APRV) using the time-controlled adaptive ventilation method (referred here as late TCAV). The second method started immediately with TCAV (referred here as early TCAV).
- The measurement of arterial blood gases and respiratory mechanics at the start of the experiment (T0) and at 30-minute intervals until the end of the 180-minute study.
- The utilization of electrical impedance tomography at T0, T30, T90 and T180 intervals to calculate mid-cranial regional ventilation.
- No statistical analysis was performed on ultrasound data. However, lung ultrasound images were obtained from three horses at various time intervals (baseline, T30, T60, T120, and T180).
Analysis of the Results
The partial pressure of arterial oxygen to fraction of inspired oxygen ratio (PaO/FiO) was significantly higher with early TCAV than with late TCAV. While the early method did not significantly affect the ratio compared to VCV, the late method, also referred to as TCAV, generated higher volumes of tidal volumes (V).
- Neither the early nor the late TCAV significantly affected the compliance (the ability to stretch) of the respiratory system or the pressures within the airways.
- The EIT showed that both early and late TCAV helped improve ventilation of the upward-facing part of the horse’s lungs.
- However, only early TCAV seemed to prevent caudal atelectasis (collapse of the lower part of the lungs) and consolidation (solidification of lung tissue), while late TCAV did not.
Drawn Conclusions
In conclusion, the study revealed that time-controlled adaptive ventilation, when applied early, succeeds in improving the oxygenation and regional ventilation in anesthetized horses. However, the later application of this method failed to yield the same results, showing no significant improvement in respiratory mechanics or oxygenation compared to volume-controlled ventilation.
Cite This Article
APA
Vicenti C, Cercone M, Nieman G, Habashi NM, Andrews P, Satalin J, Velarde P, Mitchell KJ, Louie EW, Albano V, Ali H, King A, Staffieri F, Gleed R, Bukoski A, Hopster K, Hodgson D, Adler A, Martin-Flores M, Araos J.
(2025).
Comparison of early and late time-controlled adaptive ventilation on pulmonary gas exchange in anesthetized horses.
Vet Anaesth Analg, S1467-2987(25)00138-2.
https://doi.org/10.1016/j.vaa.2025.06.007 Publication
Researcher Affiliations
- Section of Veterinary Clinics and Animal Production, Department of Precision and Regenerative Medicine and Ionian Area (DiMePre-J), University of Bari, Bari, Italy.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA; Department of Surgery, SUNY Upstate Medical Center, Syracuse, NY, USA.
- Department of Critical Care, R Adams Cowley Shock Trauma Center, Baltimore, MD, USA.
- Department of Critical Care, R Adams Cowley Shock Trauma Center, Baltimore, MD, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Section of Veterinary Clinics and Animal Production, Department of Precision and Regenerative Medicine and Ionian Area (DiMePre-J), University of Bari, Bari, Italy.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
- Department of Clinical Sciences-New Bolton Center, College of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.
- Systems and Computer Engineering, Carleton University, Ottawa, ON, Canada.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA. Electronic address: jda246@cornell.edu.
Conflict of Interest Statement
Conflict of interest statement JA: receives salary support from NIH 1R21EB034562-01. AA: owner of analyti.ca, a consulting company specializing in medical and veterinary bioimpedance technology. NH: founder of ICON. Holds a patent on a method of initiating, managing, and/or weaning APRV, as well as controlling a ventilator in accordance with the same. Royalties for book published by Springer Nature on mechanical ventilation. GN: has delivered lectures for ICON and Dräger Medical Systems, Inc. Receives salary support from NIH R01HL142702. Royalties for book published by Springer Nature on mechanical ventilation. PA: is an employee of ICON. The other authors have disclosed no conflicts of interest. The authors maintain that industry had no role in the design and conduct of the study; the collection, management, analysis, or interpretation of the data; nor the preparation, review, or approval of the manuscript.
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